#include <iostream>
#include<iomanip>
using namespace std;
int main() 
{int n;double a[3000],c[3000];
 cin>>n>>a[0]>>a[n+1];
 for(int i=1;i<=n;i++)
    cin>>c[i];
 double sum=n*a[0]+a[n+1];
 double s=0;
 for(int j=1;j<=n;j++)
   s+=(n+1-j)*c[j];

cout<<setiosflags(ios::fixed)<<setprecision(2)<<sum<<endl<<s<<endl<<(sum-2*s)/(n+1)<<endl;

system("pause");
return 0;
} 
 
 
